Automated Thread Depth Verification System for Gamor Tapping Machines Using Proximity Sensors

Abstract

This paper describes an automated depth gauge monitoring system for GTR-200 pneumatic tapping machines (100 PSI/6.9 BAR. The system utilizes an Omron E2E-X5D1-N inductive proximity sensor (30–60 mm range) in conjunction with a new L-shaped flag mechanism to ensure robust detection in hollow parts. Sensor data is processed by a programmable logic controller to realize threshold-based counting (99.95% accuracy), automatic batch reset after 10 cycles, and real-time error detection (under/over-depth conditions). Experimental testing over M4–M10 thread sizes shows 86% fewer defects than manual inspection, with a 17-day payback on the $185 implementation cost. No machine retooling is needed, and the system performs well in oily industrial settings (IP67-rated parts) with a user-friendly HMI display for real-time viewing. Size-variable thresholds (M4–M10 compatibility) and non-contact sensing that does not compromise tool integrity are the main innovations. This technology solves key industry problems in aerospace (AS9100D compliance) and automotive manufacturing by delivering high precision (±0.3mm), low cost (<$200), and simplicity of integration—making it perfect for small-to-medium-sized businesses looking to automate quality inspection in tapping processes.